Le 16/09/2010 12:18, Wolfgang Wegner a écrit : > On Thu, Sep 16, 2010 at 07:54:03PM +1000, Graeme Russ wrote: > [...] >> I have a 'cold-boot' parameter which is set by the reset vector code. I can >> use this to selectively skip 'once-only' initialisation > [...] >> I don't doubt that you are entirely correct. But there are many ways to >> skin a cat. My problem was to reduce the build->burn->boot development time >> where the burn phase was the longest. The low level boot and device >> initialisation all works and hasn't changed in quite a while, so I can rely >> on what is on my (nearly a year) old image. > > I see this feature not only nice to speed up development, sometimes > it also comes in really handy for production, too - if you have to > struggle with debugging tools that are either plain too stupid to > program some flash devices or are much slower than U-Boot, you > can simply run a specially built version from RAM and/or provide it > with an environment in RAM to do all the actual flashing for the board > production. > >> A common framework (within the bounds of cross-architecture limitations) >> would be nice > > For some targets, there may be fragments present in the code > when searching for CONFIG_MONITOR_IS_IN_RAM, which statically > disables all the low-level initialization to allow U-Boot being > loaded from a first-stage loader or debugger. But beware, it is > not always functional out-of-the-box.
For ARM926, you can disable low level init stuff and run from RAM by defining CONFIG_SKIP_LOWLEVEL_INIT. This works and is actively used in kirkwood where low level init is done by a previous loader. (independently you can disable relocation from FLASH to RAM with CONFIG_SKIP_RELOCATE_UBOOT.) Maybe we could start by standardizing a single (set of) config option(s) for skipping inits and have all boards use that? Amicalement, -- Albert. _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
